My guess is that she had things to do, Scott would only be in the way and he wanted to check out that Marina up in Berkley.
Please note: this man loved to fish. Their nursery, their little baby boy's room, was packed with fishing related items, according to criminologist Jack Levin.
I would be surprised if the sonar hit at the Marina is a human body. One thing more; Detective Ridenour said they are keeping a close watch on OTHER suspects. The two thieves, maybe?
He said that the husband had stored his fishing gear in the baby's room, which they all thought was strange.